Each year in the US, approximately 600,000 total knee replacement (TKR) surgeries are performed at a total annual cost of $15B and nearly 4.5M Americans are currently living with a TKR implant. The survival rate of TKR devices declines dramatically after ten years of use due primarily to mechanical wear. The objective of this STTR project is radically improve the durability of TKRs by modifying them to enhance the performance of the lubricating synovial fluid. The current paradigm for combating implant wear is to minimize friction by employing ultra-smooth sliding surfaces. In contrast, our approach will add to the implant's femoral component a surface texture that is designed to create hydrodynamic lubrication at low sliding velocities. Newly available ultra short pulse lasers will b used to create the designed texture on a CoCr femoral component in the form of arrays of micron-scale dimples. The lasers will achieve this in a manner that does not adversely affect the surface roughness between dimples, or the intrinsically excellent wear properties of the material. This Phase 1 project will verify the hypothesis that a surface so textured can generate full fluid lubrication at realistic knee joint sliding velocities to reduce friction and wear that eventually lead to implant failure. This research has the potential to shift current paradigms about implant bearing surfaces. This knowledge could produce a new generation of radically different, longer-lasting orthopedic implants. The method laser texturing method for modifying the implants is an established industrial process that is affordable and will allow near term transition of the lubrication enhancement technology for the benefit of patients and overall savings to the health care system. PUBLIC HEALTH RELEVANCE: Nearly 4.5 million Americans are currently benefitting from total knee replacement (TKR) implants, and new surgeries are being performed a rate of 600,000 (and $15B) per year and accelerating. The statistical failure rate of TKR implants increases dramatically after 10 years of service. This project seeks to greatly reduce wear and extend life of TKRs to avoid patient pain and disability, and reduce health care costs and risks associated with complications and revision surgery. 1